US20100246044A1 - Magnetic head-positioning system, magnetic head test system and magnetic disk test system - Google Patents
Magnetic head-positioning system, magnetic head test system and magnetic disk test system Download PDFInfo
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- US20100246044A1 US20100246044A1 US12/707,834 US70783410A US2010246044A1 US 20100246044 A1 US20100246044 A1 US 20100246044A1 US 70783410 A US70783410 A US 70783410A US 2010246044 A1 US2010246044 A1 US 2010246044A1
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- United States
- Prior art keywords
- magnetic head
- positioning system
- arm
- spindle
- magnetic
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/455—Arrangements for functional testing of heads; Measuring arrangements for heads
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/02—Control of operating function, e.g. switching from recording to reproducing
- G11B19/04—Arrangements for preventing, inhibiting, or warning against double recording on the same blank or against other recording or reproducing malfunctions
- G11B19/048—Testing of disk drives, e.g. to detect defects or prevent sudden failure
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
- G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
- G11B27/102—Programmed access in sequence to addressed parts of tracks of operating record carriers
- G11B27/105—Programmed access in sequence to addressed parts of tracks of operating record carriers of operating discs
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
- G11B27/36—Monitoring, i.e. supervising the progress of recording or reproducing
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/4806—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives
- G11B5/4826—Mounting, aligning or attachment of the transducer head relative to the arm assembly, e.g. slider holding members, gimbals, adhesive
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/4806—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives
- G11B5/4833—Structure of the arm assembly, e.g. load beams, flexures, parts of the arm adapted for controlling vertical force on the head
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/4806—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives
- G11B5/4873—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives the arm comprising piezoelectric or other actuators for adjustment of the arm
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B2220/00—Record carriers by type
- G11B2220/20—Disc-shaped record carriers
- G11B2220/25—Disc-shaped record carriers characterised in that the disc is based on a specific recording technology
- G11B2220/2508—Magnetic discs
- G11B2220/2516—Hard disks
Definitions
- the present invention relates to a magnetic head-positioning system, a magnetic head test system and a magnetic disk test system.
- the present invention specifically relates to a test system to have a magnetic head aligned with a target track on a magnetic disk, which is fit especially for an application in which an accurate positioning range for the magnetic head to be accurately positioned is relatively large.
- a magnetic head used for a magnetic head or used to store data on and reproduce the data from a magnetic disk has to be tested on its properties before it is assembled in a magnetic head system, according to Japanese Laid-open Application No. 2006-268955.
- the magnetic head is tested with a head gimbal assembly (referred to as “HGA” hereinafter) into which a head suspension and a magnetic head are assembled.
- HGA head gimbal assembly
- a piezoelectric actuator is often used for an actuator to accurately position a magnetic head. Since the piezoelectric actuator used for a fine actuator generally generates a displacement from as small as a few micron meter to 20 micron meter, it is necessary to make use of a displacement magnifying mechanism to mechanically magnify the displacement generated by the fine actuator.
- the principle of the displacement magnifying mechanism is a lever which is well known. According to Japanese Laid-open Application No. 2004.048955, the displacement generated by a piezoelectric actuator is magnified by a lever. According to Japanese Patent No. 3,612,670, vibration of the displacement magnifying mechanism is reduced by a damping member fitted in the displacement magnifying mechanism with which the displacement generated by a piezoelectric actuator is magnified.
- a HGA is made to follow a target track by a fine actuator being actuated, which is fixed on a coarse actuator.
- the target track is not always on concentric circles about the rotation center of a magnetic disk and has a first order strain on rotation, that is, eccentricity, and a strain of higher frequency components.
- the eccentricity of the target track can be created by a deviation of the center of the target track which is already written on the magnetic disk from the rotation center of the spindle. This deviation results from an assemblage error caused when a magnetic disk is assembled with a spindle.
- the eccentricity of the target track also results from the strain caused by the written target track itself which is not a complete circle.
- One of the objectives of the present invention is to provide a smaller and less costly head-positioning system which is capable of generating a larger displacement and having a better positioning accuracy.
- the magnetic head-positioning system of the present invention is suited for the magnetic head test system and the magnetic disk test system and comprises a fixing portion, at least one linear driving element fitted in the fixing portion, a plurality of hinges attached on an end portion of the linear driving element and disposed on both sides of a center line of the linear driving element, the center line of the linear driving element being in parallel with an extension-shrinkage direction of the linear driving element, and an arm having an extremity portion on which a head gimval assembly is detachably attached and a length longer than a distance between a plurality of hinge joint portions, the plurality of the hinge joint portions each of which join the hinge with a root portion of the arm and which are disposed on both sides of a center line of the arm, the center line of the arm being in parallel with a longitudinal direction of the arm.
- such a head-positioning system as small-sized, relatively cheap, generating a relatively large displacement and having a good positioning accuracy, is provided.
- the magnetic head-positioning system of the present invention comprises a piezoelectric actuator fitted in the fixing portion, a plurality of hinges attached on an end portion of the piezoelectric actuator and disposed on both sides of a center line of the piezoelectric actuator, the center line of the piezoelectric actuator being in parallel with an extension-shrinkage direction of the piezoelectric actuator, an arm having an extremity portion on which a head gimval assembly is detachably attached and a length longer than a distance between a plurality of hinge joint portions, the plurality of the hinge joint portions each of which joins the hinge with a root portion of the arm and which are disposed on both sides of a center line of the arm, the center line of the arm being in parallel with a longitudinal direction of the arm, and a damping material connecting the end portion of the arm with the fixing portion, wherein a HGA is positioned by rotation of the arm caused by the piezoelectric actuator elongating and shrinking.
- a magnetic head test system and a magnetic disk test system are provided, which are capable of testing a magnetic disk with a target track having large eccentricity and accurately testing a magnetic head using the magnetic disk with a target track having large eccentricity.
- FIG. 1 is a top perspective view of a magnetic head-positioning system actuation part in accordance with the first embodiment of the present invention.
- FIG. 2 is an explanation figure illustrating the operation of the magnetic head-positioning system actuation part shown in FIG. 1 .
- FIG. 3 is an explanation figure of a magnetic head-positioning system actuation part in accordance with the second embodiment of the present invention.
- FIG. 4 indicates the frequency response of the magnetic head-positioning system shown in FIG. 1 .
- FIG. 5 indicates the frequency response of the magnetic head-positioning system shown in FIG. 3 .
- FIG. 6 is a top perspective view of an actuation part of a magnetic disk test system actuation part in accordance with the third embodiment of the present invention.
- FIG. 7 A is an explanation figure indicating an effect of the actuation part of the comparison sample.
- FIG. 7B is an explanation figure indicating an effect of the actuation part of the present invention.
- FIG. 1 is a top perspective view of a magnetic head-positioning system actuation part 100 in accordance with the first embodiment of the present invention.
- FIG. 2 is an explanation figure illustrating the operation of the magnetic head-positioning system actuation part 100 shown in FIG. 1 .
- the magnetic head-positioning system actuation part 100 comprises a piezoactuator 2 fitted in a fixing portion 1 , hinges 4 a , 4 b , an arm 5 and hinge joint portions 8 a , 8 b .
- the hinges 4 a , 4 b are disposed over the end portion of the piezoactuator 2 and one of the hinges 4 a , 4 b is on the right side of the center line 3 of the piezoactuator 2 in parallel with the extension-shrinkage direction of the piezoactuator 2 with the other of the hinges 4 a , 4 b disposed on the left side.
- the hinges 4 a , 4 b are connected with a root portion 6 of the arm 5 through the hinge joint portions 8 a , 8 b respectively.
- the hinge joint portions 8 a , 8 b are disposed on the root portion 6 and one of the hinge joint portions 8 a , 8 b is disposed on the right side of the center line 7 of the arm 5 in its longitudinal direction with the other on the left side.
- An arm length 10 is much longer than a distance 9 between the hinge joint portions 8 a , 8 b .
- the arm 5 has a HGA 12 detachably fixed on the end portion 11 .
- the hinges 4 a , 4 b are displaced so as to open as indicated by arrows 13 a , 13 b in FIG. 2 and the hinge joint portion 8 a is strained while the hinge joint portion 8 b is being compressed because both of the hinges 4 a , 4 b which are displaced and opened are connected with the root portion 6 of the arm 5 .
- the arm 5 and the HGA 12 fixed on the arm 5 rotate as indicated by an arrow 15 .
- the reason why the piezoelectric actuator 2 constituted by piezoelectric elements is used for the actuator to press the hinges 4 a , 4 b in the magnetic head-positioning system actuation part 100 is that features of piezoelectric elements are suited for the actuator for positioning.
- the piezoelectric element has such features as a generating force being large while the size is small, high displacement resolution, lower energy consumption than the electromagnetic type actuator and no magnetic flux leakage because of no need for magnetic field.
- the movable distance of the HGA 12 at the extremity portion 121 becomes large as compared with the displacement generated on the piezoelectric actuator 2 . Since both the arm length 10 and the distance 9 between the hinge joint portions 8 a , 8 b are determined regardless of the size of the piezoelectric actuator 2 , it is possible to make the movable distance of the extremity portion 121 of the HGA 12 larger up to a limit beyond which vibration is too large to be allowed without being restricted by the size of the piezoelectric actuator 2 .
- the center line 3 of the piezoelectric actuator 2 in its extension-shrinkage direction is set perpendicular to the center line 7 of the arm 5 in its longitudinal direction in this embodiment.
- the magnetic head-positioning actuation part 100 in which the arm 5 is rotated by applying a force to the root portion 6 of the arm 5 , it is possible to rotate the arm 5 by using a fulcrum point and an application point on force.
- the arm 5 is rotated without any fulcrum point by applying a couple of different forces applied to the root portion 6 in this embodiment. Therefore it is possible to avoid a problem with stress concentration at a fulcrum point and instability of operation attributed to a position deviation between the rotation center of the arm 5 and the fulcrum point.
- FIG. 7 A is an explanation figure indicating an effect of the actuation part of the comparison sample.
- FIG. 7B is an explanation figure indicating an effect of the actuation part of the present invention.
- the force (indicated by small arrows in FIG. 7A ) generated by a piezoelectric actuator is applied to the fixing portion and a hinge and is transmitted in only a direction (indicated by a large arrow) through the hinge.
- the force indicated by small arrows in FIG.
- FIG. 3 is a top perspective view of a magnetic head-positioning system actuation part 200 in accordance with the second embodiment of the present invention. Is
- the magnetic head-positioning system actuation part 200 comprises a piezoactuator 2 fitted in a fixing portion 1 , hinges 4 a , 4 b , an arm 5 and a damping rubber 21 .
- the hinges 4 a , 4 b are disposed over the end portion of the piezoactuator 2 and one of the hinges 4 a , 4 b is on the right side of the center line 3 of the piezoactuator 2 in parallel with the extension-shrinkage direction of the piezoactuator 2 with the other of the hinges 4 a , 4 b disposed on the left side.
- the hinges 4 a , 4 b are connected with a root portion 6 of the arm 5 through the hinge joint portions 8 a , 8 b respectively.
- the hinge joint portions 8 a , 8 b are disposed on the root portion 6 and an arm length 10 is much longer than a distance 9 between the hinge joint portions 8 a , 8 b .
- the arm 5 has a HGA 12 detachably fixed on the end portion 11 and a damping rubber which is jointed with both the end portion 11 of the arm 5 and the fixing portion 1 and connects them.
- the magnetic head-positioning system actuation part 100 of the first embodiment and the damping rubber 21 connecting the end portion 11 constitute the magnetic head-positioning system actuation part 200 of this embodiment.
- the magnetic head-positioning system actuation part 200 operates the same way as the magnetic head-positioning system actuation part 100 of the first embodiment does.
- FIG. 4 indicates the frequency-vibration response of the magnetic head-positioning system actuation part 100 shown in FIG. 1 while FIG. 5 indicates the frequency-vibration response of the magnetic head-positioning system actuation part 200 shown in FIG. 3 .
- Each figure indicates vibration of the extremity portion 121 of the HGA 12 in response to the input voltage to the piezoactuator 2 .
- gains of these relatively large vibration modes decrease significantly in FIG. 5 . Accordingly more accurate positioning is possible with the magnetic head-positioning system actuation part 200 of this embodiment.
- FIG. 6 indicates the third embodiment of the present invention and is a top perspective view of a magnetic disk test system actuation part in accordance with the third embodiment of the present invention, which utilizes the magnetic head-positioning system actuation part 200 .
- the magnetic disk test system is a system which reproduces both magnetic information magnetically written on a magnetic disk 31 in advance and magnetic information magnetically written on the magnetic disk 31 with a magnetic head attached on the extremity portion 121 of the HGA 12 and tests the magnetic disk property.
- the magnetic disk test system actuation part 300 comprises the magnetic disk 31 , a base plate 32 , a spindle 33 , a coarse actuator 34 and a magnetic head-positioning system actuation part 200 of the second embodiment.
- the coarse actuator 34 and the spindle 33 are fixed on the base plate 32 .
- the magnetic disk 31 is rotatably and detachably attached on the spindle 33 .
- the magnetic head-positioning system actuation part 200 is fixed on a coarse positioning table 35 of the coarse actuator 34 .
- the magnetic head-positioning system actuation part 200 is capable of enlarging a traveling distance of the extremity portion 121 of the HGA 12 , it is difficult for the magnetic head-positioning system actuation part 200 to have the extremity portion 121 cover a whole information written area of the magnetic disk whose diameter length is as long as a few tens of millimeters. Therefore the HGA 12 is positioned with the magnetic head-positioning system actuation part 200 after the magnetic head-positioning system actuation part 200 is coarsely positioned at a predetermined position. According to this positioning method, it is possible to position accurately the magnetic head attached on the extremity portion 121 of the HGA 12 at any specific point in the entire information written area of the magnetic disk and the magnetic disk is to be tested accurately.
- the HGA 12 is positioned on the magnetic disk 31 with the coarse actuator 34 and the magnetic head-positioning system actuation part 200 in this embodiment.
- the magnetic head test system having the three actuators has an effect of increasing freedom for positioning control and positioning function in addition to the effect of this embodiment.
- the fourth embodiment of the present invention is intended for a magnetic head test system utilizing a magnetic head-positioning system actuation part described in the third embodiment.
- the magnetic head-positioning system actuation part consists of constituents as described in FIG. 3 and the magnetic head test actuation part includes constituents described in FIG. 6 .
- the magnetic head test system is a system which reproduces both magnetic information magnetically written on a magnetic disk in advance and magnetic information magnetically written on the magnetic disk 31 with a magnetic head attached on the extremity portion 121 of the HGA 12 and tests the property of the HGA 12 .
- the magnetic head test system of the fourth embodiment is capable of positioning accurately the magnetic head attached on the extremity portion 121 of the HGA 12 in the entire information written area of the magnetic disk 31 and testing accurately the HGA 12 .
- the HGA 12 is positioned on the magnetic disk 31 with the coarse actuator 34 and the magnetic head-positioning system actuation part 200 in this embodiment.
- the magnetic head test system having the three actuators has an effect of increasing freedom for positioning control and positioning function in addition to the effect of this embodiment.
- the present invention is applied to a magnetic disk test system.
- it is also possible to apply the present invention to other systems such as a magnetic head-positioning control system, a magnetic head test system and a system to evaluate both a magnetic disk and a magnetic head.
Landscapes
- Moving Of The Head To Find And Align With The Track (AREA)
- Supporting Of Heads In Record-Carrier Devices (AREA)
- Moving Of Heads (AREA)
Abstract
A magnetic head-positioning system to accurately test a magnetic disk and a magnetic head, comprises a plurality of hinges attached on an end portion of a linear driving element and disposed on both sides of a center line of the linear driving element, which is in parallel with an extension-shrinkage direction of the linear driving element, and an arm having a length longer than a distance between a plurality of hinge joint portions, the plurality of the hinge joint portions each of which join the hinge with a root portion of the arm and which are disposed on both sides of a center line of the arm which is in parallel with a longitudinal direction of the arm. The arm has an extremity portion on which a head gimval assembly is detachably attached and this head gimval assembly is positioned.
Description
- The present application claims priority from Japanese Patent Application JP2009-073069 filed on Mar. 25, 2009, the content of which is incorporated by reference into this application.
- 1. Field of the Invention
- The present invention relates to a magnetic head-positioning system, a magnetic head test system and a magnetic disk test system. The present invention specifically relates to a test system to have a magnetic head aligned with a target track on a magnetic disk, which is fit especially for an application in which an accurate positioning range for the magnetic head to be accurately positioned is relatively large.
- 2. Description of the Related Art
- A magnetic head used for a magnetic head or used to store data on and reproduce the data from a magnetic disk has to be tested on its properties before it is assembled in a magnetic head system, according to Japanese Laid-open Application No. 2006-268955. The magnetic head is tested with a head gimbal assembly (referred to as “HGA” hereinafter) into which a head suspension and a magnetic head are assembled. When the magnetic head is tested, data is stored on and reproduced from a magnetic disk with the magnetic head kept floated over a magnetic disk being rotated by a spindle motor.
- A piezoelectric actuator is often used for an actuator to accurately position a magnetic head. Since the piezoelectric actuator used for a fine actuator generally generates a displacement from as small as a few micron meter to 20 micron meter, it is necessary to make use of a displacement magnifying mechanism to mechanically magnify the displacement generated by the fine actuator. The principle of the displacement magnifying mechanism is a lever which is well known. According to Japanese Laid-open Application No. 2004.048955, the displacement generated by a piezoelectric actuator is magnified by a lever. According to Japanese Patent No. 3,612,670, vibration of the displacement magnifying mechanism is reduced by a damping member fitted in the displacement magnifying mechanism with which the displacement generated by a piezoelectric actuator is magnified.
- According to Japanese Patent No. 3,539,332, there is another type of a displacement magnifying mechanism for an actuator which has an arm whose root portion is displaced by a couple of actuators to generate displacements and which turns as the actuators generate displacements and generates a magnified displacement at the extremity portion of the arm.
- In the test system to test a magnetic head, a HGA is made to follow a target track by a fine actuator being actuated, which is fixed on a coarse actuator. The target track is not always on concentric circles about the rotation center of a magnetic disk and has a first order strain on rotation, that is, eccentricity, and a strain of higher frequency components. The eccentricity of the target track can be created by a deviation of the center of the target track which is already written on the magnetic disk from the rotation center of the spindle. This deviation results from an assemblage error caused when a magnetic disk is assembled with a spindle. The eccentricity of the target track also results from the strain caused by the written target track itself which is not a complete circle. In the case of the magnetic disk of Discrete Track Media (DTM) or Bit Pattern Media (BPM), on which the target track is written in advance, the position deviation of the center of the target track from the rotation center of the spindle is created when the magnetic disk is mounted and the eccentricity due to this deviation tends to be relatively large. If this eccentricity becomes larger, the stroke of the fine actuator to drive the HGA on which a magnetic head is mounted needs to be larger.
- Furthermore, there has been a need to make the fine actuator smaller and less costly.
- One of the objectives of the present invention is to provide a smaller and less costly head-positioning system which is capable of generating a larger displacement and having a better positioning accuracy.
- A specific feature of the present invention is that the magnetic head-positioning system of the present invention is suited for the magnetic head test system and the magnetic disk test system and comprises a fixing portion, at least one linear driving element fitted in the fixing portion, a plurality of hinges attached on an end portion of the linear driving element and disposed on both sides of a center line of the linear driving element, the center line of the linear driving element being in parallel with an extension-shrinkage direction of the linear driving element, and an arm having an extremity portion on which a head gimval assembly is detachably attached and a length longer than a distance between a plurality of hinge joint portions, the plurality of the hinge joint portions each of which join the hinge with a root portion of the arm and which are disposed on both sides of a center line of the arm, the center line of the arm being in parallel with a longitudinal direction of the arm.
- According to this specific feature of the present invention, such a head-positioning system as small-sized, relatively cheap, generating a relatively large displacement and having a good positioning accuracy, is provided.
- Another specific feature of the present invention is that the magnetic head-positioning system of the present invention comprises a piezoelectric actuator fitted in the fixing portion, a plurality of hinges attached on an end portion of the piezoelectric actuator and disposed on both sides of a center line of the piezoelectric actuator, the center line of the piezoelectric actuator being in parallel with an extension-shrinkage direction of the piezoelectric actuator, an arm having an extremity portion on which a head gimval assembly is detachably attached and a length longer than a distance between a plurality of hinge joint portions, the plurality of the hinge joint portions each of which joins the hinge with a root portion of the arm and which are disposed on both sides of a center line of the arm, the center line of the arm being in parallel with a longitudinal direction of the arm, and a damping material connecting the end portion of the arm with the fixing portion, wherein a HGA is positioned by rotation of the arm caused by the piezoelectric actuator elongating and shrinking.
- According to this specific feature of the present invention, a magnetic head test system and a magnetic disk test system are provided, which are capable of testing a magnetic disk with a target track having large eccentricity and accurately testing a magnetic head using the magnetic disk with a target track having large eccentricity.
-
FIG. 1 is a top perspective view of a magnetic head-positioning system actuation part in accordance with the first embodiment of the present invention. -
FIG. 2 is an explanation figure illustrating the operation of the magnetic head-positioning system actuation part shown inFIG. 1 . -
FIG. 3 is an explanation figure of a magnetic head-positioning system actuation part in accordance with the second embodiment of the present invention. -
FIG. 4 indicates the frequency response of the magnetic head-positioning system shown inFIG. 1 . -
FIG. 5 indicates the frequency response of the magnetic head-positioning system shown inFIG. 3 . -
FIG. 6 is a top perspective view of an actuation part of a magnetic disk test system actuation part in accordance with the third embodiment of the present invention. -
FIG. 7 A is an explanation figure indicating an effect of the actuation part of the comparison sample. -
FIG. 7B is an explanation figure indicating an effect of the actuation part of the present invention. - Hereinafter are explained embodiments of the present invention.
-
FIG. 1 is a top perspective view of a magnetic head-positioningsystem actuation part 100 in accordance with the first embodiment of the present invention.FIG. 2 is an explanation figure illustrating the operation of the magnetic head-positioningsystem actuation part 100 shown inFIG. 1 . - As is shown in
FIG. 1 andFIG. 2 , the magnetic head-positioningsystem actuation part 100 comprises apiezoactuator 2 fitted in afixing portion 1,hinges arm 5 and hingejoint portions hinges piezoactuator 2 and one of thehinges piezoactuator 2 in parallel with the extension-shrinkage direction of thepiezoactuator 2 with the other of thehinges hinges arm 5 through the hingejoint portions joint portions joint portions arm 5 in its longitudinal direction with the other on the left side. Anarm length 10 is much longer than a distance 9 between the hingejoint portions arm 5 has aHGA 12 detachably fixed on theend portion 11. - As indicated in
FIG. 2 , if thepiezoactuator 2 elongates, thehinges arrows FIG. 2 and thehinge joint portion 8 a is strained while the hingejoint portion 8 b is being compressed because both of thehinges arm 5. As a result, thearm 5 and theHGA 12 fixed on thearm 5 rotate as indicated by anarrow 15. - The reason why the
piezoelectric actuator 2 constituted by piezoelectric elements is used for the actuator to press thehinges system actuation part 100 is that features of piezoelectric elements are suited for the actuator for positioning. The piezoelectric element has such features as a generating force being large while the size is small, high displacement resolution, lower energy consumption than the electromagnetic type actuator and no magnetic flux leakage because of no need for magnetic field. - In this embodiment, if the
arm length 10 is set much longer than the distance 9 between the hingejoint portions HGA 12 at theextremity portion 121 becomes large as compared with the displacement generated on thepiezoelectric actuator 2. Since both thearm length 10 and the distance 9 between the hingejoint portions piezoelectric actuator 2, it is possible to make the movable distance of theextremity portion 121 of theHGA 12 larger up to a limit beyond which vibration is too large to be allowed without being restricted by the size of thepiezoelectric actuator 2. - Moreover the center line 3 of the
piezoelectric actuator 2 in its extension-shrinkage direction is set perpendicular to the center line 7 of thearm 5 in its longitudinal direction in this embodiment. As a result the generating force of thepiezoelectric actuator 2 is efficiently transmitted. - In the magnetic head-
positioning actuation part 100 in which thearm 5 is rotated by applying a force to the root portion 6 of thearm 5, it is possible to rotate thearm 5 by using a fulcrum point and an application point on force. On the other hand thearm 5 is rotated without any fulcrum point by applying a couple of different forces applied to the root portion 6 in this embodiment. Therefore it is possible to avoid a problem with stress concentration at a fulcrum point and instability of operation attributed to a position deviation between the rotation center of thearm 5 and the fulcrum point. - In the present embodiment, there is no need to make use of a couple of actuators in order to apply a couple of different forces on the
root portion 5, although it is possible to apply a couple of different forces on theroot portion 5 by making use of only onepiezoelectric actuator 2. Obviously this embodiment makes it possible to have a less costly and smaller magnetic head-positioning system than an actuation structure making use of a couple of actuators. - Next an explanation is given on functions, effects and an operation principle of the present invention.
FIG. 7 A is an explanation figure indicating an effect of the actuation part of the comparison sample.FIG. 7B is an explanation figure indicating an effect of the actuation part of the present invention. In the case of the comparison sample, the force (indicated by small arrows inFIG. 7A ) generated by a piezoelectric actuator is applied to the fixing portion and a hinge and is transmitted in only a direction (indicated by a large arrow) through the hinge. On the other hand, in the case of an actuator structure of the present invention, the force (indicated by small arrows inFIG. 7B ) which is generated from a piezoelectric actuator is transmitted and applied to the fixing portion and a hinge, and transmitted in two different directions (indicated by large arrows inFIG. 7B ) through the hinge. There are a couple of excellent effects attributed to this actuator structure. - (1) Magnification rate of device's displacement to actuator's displacement becomes larger with a displacement difference being magnified.
(2) Actuator's generating force being divided in two directions corresponds to a couple of hinges being integrally formed. As a result, property variation of the displacement magnification section which is attributed to a hinge dimension error is made smaller (the total property variation of the displacement magnification section due to production errors corresponds to the average on the plurality of the hinge dimension errors). -
FIG. 3 is a top perspective view of a magnetic head-positioning system actuationpart 200 in accordance with the second embodiment of the present invention. Is - The magnetic head-positioning system actuation
part 200 comprises apiezoactuator 2 fitted in a fixingportion 1, hinges 4 a, 4 b, anarm 5 and a dampingrubber 21. The hinges 4 a, 4 b are disposed over the end portion of thepiezoactuator 2 and one of thehinges piezoactuator 2 in parallel with the extension-shrinkage direction of thepiezoactuator 2 with the other of thehinges arm 5 through the hingejoint portions joint portions arm length 10 is much longer than a distance 9 between the hingejoint portions arm 5 has aHGA 12 detachably fixed on theend portion 11 and a damping rubber which is jointed with both theend portion 11 of thearm 5 and the fixingportion 1 and connects them. The magnetic head-positioning system actuationpart 100 of the first embodiment and the dampingrubber 21 connecting theend portion 11 constitute the magnetic head-positioning system actuationpart 200 of this embodiment. - The magnetic head-positioning system actuation
part 200 operates the same way as the magnetic head-positioning system actuationpart 100 of the first embodiment does. -
FIG. 4 indicates the frequency-vibration response of the magnetic head-positioning system actuationpart 100 shown inFIG. 1 whileFIG. 5 indicates the frequency-vibration response of the magnetic head-positioning system actuationpart 200 shown inFIG. 3 . Each figure indicates vibration of theextremity portion 121 of theHGA 12 in response to the input voltage to thepiezoactuator 2. There are a couple of relatively large vibration modes at the frequency a little smaller than 2 kHz and around the frequency of 5 kHz as seen fromFIG. 4 . However gains of these relatively large vibration modes decrease significantly inFIG. 5 . Accordingly more accurate positioning is possible with the magnetic head-positioning system actuationpart 200 of this embodiment. -
FIG. 6 indicates the third embodiment of the present invention and is a top perspective view of a magnetic disk test system actuation part in accordance with the third embodiment of the present invention, which utilizes the magnetic head-positioning system actuationpart 200. - The magnetic disk test system is a system which reproduces both magnetic information magnetically written on a
magnetic disk 31 in advance and magnetic information magnetically written on themagnetic disk 31 with a magnetic head attached on theextremity portion 121 of theHGA 12 and tests the magnetic disk property. - The magnetic disk test system actuation
part 300 comprises themagnetic disk 31, abase plate 32, aspindle 33, acoarse actuator 34 and a magnetic head-positioning system actuationpart 200 of the second embodiment. Thecoarse actuator 34 and thespindle 33 are fixed on thebase plate 32. Themagnetic disk 31 is rotatably and detachably attached on thespindle 33. The magnetic head-positioning system actuationpart 200 is fixed on a coarse positioning table 35 of thecoarse actuator 34. - Although the magnetic head-positioning system actuation
part 200 is capable of enlarging a traveling distance of theextremity portion 121 of theHGA 12, it is difficult for the magnetic head-positioning system actuationpart 200 to have theextremity portion 121 cover a whole information written area of the magnetic disk whose diameter length is as long as a few tens of millimeters. Therefore theHGA 12 is positioned with the magnetic head-positioning system actuationpart 200 after the magnetic head-positioning system actuationpart 200 is coarsely positioned at a predetermined position. According to this positioning method, it is possible to position accurately the magnetic head attached on theextremity portion 121 of theHGA 12 at any specific point in the entire information written area of the magnetic disk and the magnetic disk is to be tested accurately. - As has been explained, the
HGA 12 is positioned on themagnetic disk 31 with thecoarse actuator 34 and the magnetic head-positioning system actuationpart 200 in this embodiment. However, there may be a third actuator attached between thecoarse actuator 34 and the magnetic head-positioning system actuationpart 200. The magnetic head test system having the three actuators has an effect of increasing freedom for positioning control and positioning function in addition to the effect of this embodiment. - The fourth embodiment of the present invention is intended for a magnetic head test system utilizing a magnetic head-positioning system actuation part described in the third embodiment. Accordingly the magnetic head-positioning system actuation part consists of constituents as described in
FIG. 3 and the magnetic head test actuation part includes constituents described inFIG. 6 . The magnetic head test system is a system which reproduces both magnetic information magnetically written on a magnetic disk in advance and magnetic information magnetically written on themagnetic disk 31 with a magnetic head attached on theextremity portion 121 of theHGA 12 and tests the property of theHGA 12. - With this structure as explained, the magnetic head test system of the fourth embodiment is capable of positioning accurately the magnetic head attached on the
extremity portion 121 of theHGA 12 in the entire information written area of themagnetic disk 31 and testing accurately theHGA 12. - As is the case with the third embodiment, the
HGA 12 is positioned on themagnetic disk 31 with thecoarse actuator 34 and the magnetic head-positioning system actuationpart 200 in this embodiment. However, there may be a third actuator attached between thecoarse actuator 34 and the magnetic head-positioning system actuationpart 200. The magnetic head test system having the three actuators has an effect of increasing freedom for positioning control and positioning function in addition to the effect of this embodiment. - Although embodiments of the present invention have been described, the present invention should not be limited to what has been described. There are other various embodiments within the scope of the present invention.
- The embodiments described above indicate that the present invention is applied to a magnetic disk test system. However it is also possible to apply the present invention to other systems such as a magnetic head-positioning control system, a magnetic head test system and a system to evaluate both a magnetic disk and a magnetic head.
Claims (10)
1. A magnetic head-positioning system comprising,
a fixing portion,
at least one linear driving element fitted in the fixing portion,
a plurality of hinges attached on an end portion of the linear driving element and disposed on both sides of a center line of the linear driving element, the center line of the linear driving element being in parallel with an extension-shrinkage direction of the linear driving element, and
an arm having an extremity portion on which a head gimval assembly is detachably attached and a length longer than a distance between a plurality of hinge joint portions, the plurality of the hinge joint portions each of which joins the hinge with a root portion of the arm and which are disposed on both sides of a center line of the arm, the center line of the arm being in parallel with a longitudinal direction of the arm.
2. The magnetic head-positioning system as described in claim 1 , wherein the end portion of the arm is connected with the fixing portion through a damping material.
3. A magnetic head-positioning system as described in the claim 1 , wherein the linear driving element is a piezoelectric actuator.
4. A magnetic head-positioning system as described in the claim 2 , wherein the linear driving element is a piezoelectric actuator.
5. A magnetic disk test system comprising,
a magnetic head-positioning system as described in the claim 1 ,
a coarse actuator for supporting and moving the magnetic head-positioning system,
a spindle for rotating a circular disk, and
a base plate for supporting the coarse actuator and the spindle.
6. A magnetic disk test system comprising,
a magnetic head-positioning system as described in the claim 2 ,
a coarse actuator for supporting and moving the magnetic head-positioning system,
a spindle for rotating a circular disk, and
a base plate for supporting the coarse actuator and the spindle.
7. A magnetic disk test system comprising,
a magnetic head-positioning system as described in the claim 3 ,
a coarse actuator for supporting and moving the magnetic head-positioning system,
a spindle for rotating a circular disk, and
a base plate for supporting the coarse actuator and the spindle.
8. A magnetic head test system comprising
a magnetic head-positioning system as described in the claim 1 ,
a coarse actuator for supporting and moving the magnetic head-positioning system,
a spindle for rotating a circular disk, and
a base plate for supporting the coarse actuator and the spindle.
9. A magnetic head test system comprising
a magnetic head-positioning system as described in the claim 2 ,
a coarse actuator for supporting and moving the magnetic head-positioning system,
a spindle for rotating a circular disk, and
a base plate for supporting the coarse actuator and the spindle.
10. A magnetic head test system comprising
a magnetic head-positioning system as described in the claim 3 ,
a coarse actuator for supporting and moving the magnetic head-positioning system,
a spindle for rotating a circular disk, and
a base plate for supporting the coarse actuator and the spindle.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2009-073069 | 2009-03-25 | ||
JP2009073069A JP2010225247A (en) | 2009-03-25 | 2009-03-25 | Magnetic head positioning device, magnetic head testing device, and magnetic disk testing device |
Publications (2)
Publication Number | Publication Date |
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US20100246044A1 true US20100246044A1 (en) | 2010-09-30 |
US8493692B2 US8493692B2 (en) | 2013-07-23 |
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US12/707,834 Expired - Fee Related US8493692B2 (en) | 2009-03-25 | 2010-02-18 | Position determining system with arm center line crossing expanding/contracting direction of hinged actuator unit |
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US (1) | US8493692B2 (en) |
JP (1) | JP2010225247A (en) |
Families Citing this family (3)
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JP5662905B2 (en) * | 2011-08-25 | 2015-02-04 | 株式会社日立ハイテクノロジーズ | Fine motion actuator and magnetic head or magnetic disk inspection device |
JP2013211072A (en) * | 2012-03-30 | 2013-10-10 | Hitachi High-Technologies Corp | Magnetic head positioning device and magnetic head inspection device |
WO2014103460A1 (en) * | 2012-12-28 | 2014-07-03 | 株式会社村田製作所 | Medium for magnetic sensor test, method for testing magnetic sensor, and method for manufacturing medium for magn etic sensor test |
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US5189578A (en) * | 1989-06-28 | 1993-02-23 | Hitachi, Ltd. | Disk system with sub-actuators for fine head displacement |
US6233124B1 (en) * | 1998-11-18 | 2001-05-15 | Seagate Technology Llc | Piezoelectric microactuator suspension assembly with improved stroke length |
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US20020057517A1 (en) * | 2000-11-13 | 2002-05-16 | Hitoshi Takagi | Head clamping apparatus for magnetic disk tester and magnetic disk tester |
US6498704B1 (en) * | 2000-02-23 | 2002-12-24 | Maxtor Corporation | Disk drive with viscoelastic damper disposed between adjacent load beams |
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US20100097727A1 (en) * | 2008-10-20 | 2010-04-22 | Seagate Technology Llc | Recessed base plate for data transducer suspension |
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JP3539332B2 (en) | 2000-02-23 | 2004-07-07 | 株式会社日立製作所 | Disk unit |
JP4451980B2 (en) * | 2000-11-13 | 2010-04-14 | ユニパルス株式会社 | Head clamp device for disk characteristic evaluation device |
JP2004048955A (en) | 2002-07-15 | 2004-02-12 | Denshi Seiki:Kk | Direct action type displacement enlarging mechanism and manufacturing method thereof |
JP2004268955A (en) | 2003-03-06 | 2004-09-30 | Seiko Sangyo Kk | Stretch packaging apparatus utilizing fork of lift truck |
JP3612670B1 (en) * | 2004-03-15 | 2005-01-19 | 秋田県 | Actuator damping method and actuator |
JP2006268955A (en) | 2005-03-24 | 2006-10-05 | Hitachi High-Technologies Corp | Magnetic head positioning controller, magnetic head tester, and magnetic disk tester |
-
2009
- 2009-03-25 JP JP2009073069A patent/JP2010225247A/en active Pending
-
2010
- 2010-02-18 US US12/707,834 patent/US8493692B2/en not_active Expired - Fee Related
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
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US5189578A (en) * | 1989-06-28 | 1993-02-23 | Hitachi, Ltd. | Disk system with sub-actuators for fine head displacement |
US6233124B1 (en) * | 1998-11-18 | 2001-05-15 | Seagate Technology Llc | Piezoelectric microactuator suspension assembly with improved stroke length |
US6239953B1 (en) * | 1999-10-15 | 2001-05-29 | Magnecomp Corp. | Microactuated disk drive suspension with heightened stroke sensitivity |
US6498704B1 (en) * | 2000-02-23 | 2002-12-24 | Maxtor Corporation | Disk drive with viscoelastic damper disposed between adjacent load beams |
US20020057517A1 (en) * | 2000-11-13 | 2002-05-16 | Hitoshi Takagi | Head clamping apparatus for magnetic disk tester and magnetic disk tester |
US20100097726A1 (en) * | 2008-10-20 | 2010-04-22 | Seagate Technology Llc | Cost reduced microactuator suspension |
US20100097727A1 (en) * | 2008-10-20 | 2010-04-22 | Seagate Technology Llc | Recessed base plate for data transducer suspension |
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US8493692B2 (en) | 2013-07-23 |
JP2010225247A (en) | 2010-10-07 |
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